JP2012084424A - Secondary battery and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a secondary battery with a large area laminated power storage element which can be handled without deforming the power storage element, and in which the power storage element can be housed in a battery can without being deflected, and connection work of a power collection lead and an external terminal is facilitated, and to provide a manufacturing method therefor.SOLUTION: In the secondary batteries (RB1, RB2, RB3), a battery can is constituted of a main container CA1, and a sub-container CA2 having a volume smaller than that of the main container. An external terminal 7 is provided in the sub-container CA2, an electrode group 1 is laminated on the sub-container, a power collection lead 5 provided in the electrode group 1 is connected with the external terminal 7, and then the sub-container is attached together with the main container CA1 thus constituting a battery can. A manufacturing method therefor is also provided.

Description

  The present invention relates to a secondary battery, and more particularly, to a laminated secondary battery in which a plurality of positive and negative electrode plates are laminated and a method for manufacturing the same.

  In recent years, lithium secondary batteries have been used as power source batteries for portable electronic devices such as mobile phones and notebook computers because they have a high energy density and can be reduced in size and weight. Further, since the capacity can be increased, it has been attracting attention as a motor drive power source for electric vehicles (EV) and hybrid electric vehicles (HEV), and a storage battery for power storage.

  In the lithium secondary battery, an electrode group in which a positive electrode plate and a negative electrode plate are arranged opposite to each other with a separator interposed therebetween is housed in an outer case constituting a battery can, filled with an electrolyte, and positive electrode current collectors of a plurality of positive electrode plates A positive current collecting lead coupled to the tab; a positive external terminal electrically connected to the positive current collecting lead; a negative current collecting lead coupled to the negative current collecting tabs of the plurality of negative electrode plates; and the negative current collecting lead. It is set as the structure provided with the negative electrode external terminal electrically connected with an electrical lead.

  As the electrode group, a wound type and a laminated type are known. The wound electrode group has a configuration in which a separator is interposed between a positive electrode plate and a negative electrode plate, and is integrally wound. The laminated electrode group has a positive electrode plate and a negative electrode plate interposed via a separator. It is the structure which laminated | stacked multiple layers.

  In a lithium secondary battery including a stacked electrode group, an electrode group in which a plurality of layers of a positive electrode plate and a negative electrode plate are stacked via a separator is housed in an outer case and filled with a non-aqueous electrolyte, respectively. A positive current collecting lead connected to the positive current collecting tab of the positive electrode plate, an external terminal electrically connected to the positive current collecting lead, and a negative current collecting lead connected to the negative current collecting tab of the negative electrode plate And an external terminal electrically connected to the negative electrode current collecting lead.

  For this purpose, a normal secondary battery accommodates one electrode group in one battery can and is provided with one positive external terminal and one negative external terminal. In order to produce a large capacity secondary battery, it is necessary to increase the area of the positive electrode plate and the negative electrode plate, increase the number of stacked layers, and increase the amount of electrolyte to be filled.

  However, when a large-area battery canister is assembled into a large-sized battery can (a power generation / storage unit including a stacked electrode group and a current collecting lead), a positive electrode plate, a negative electrode plate, and a separator are stacked. When the elements are handled as a unit, there is a risk that a gap between the electrodes may be formed due to deflection or distortion of the heavy electrode group.

  Further, the current collecting lead of the large capacity secondary battery is thick in order to pass a large current. When the current collecting lead is thick, it is difficult to perform fine position adjustment, and the lead is not properly handled when the current collecting lead is connected to an external terminal. Further, when the current collecting lead is lengthened, the electrical resistance is increased and the battery characteristics are deteriorated. Therefore, the current collecting lead is preferably as short as possible.

  However, after the storage element is accommodated in the battery can, the configuration in which the current collecting lead provided on the storage element is connected to the terminal portion on the battery can side, in order to ensure the connection and facilitate the connection work, It is desirable to keep the current collecting lead long. For example, a non-aqueous electrolyte battery in which a current collecting lead having one end connected to a power storage element is bent in a U shape and connected to an external terminal is disclosed (for example, see Patent Document 1).

JP 2001-93571 A

  If the plane area of the stacked electrode group is increased in order to increase the capacity of the power storage element, it will be bent during transportation, causing a problem in handling. When the stacked electrode group is bent, static electricity is generated or gaps are formed, and foreign substances are easily mixed, resulting in a short circuit risk. Thus, if the handling property is deteriorated at the time of manufacture, the yield is deteriorated due to a short circuit or the like, which causes a material loss.

  Further, in the configuration in which the current collecting lead on the power storage element side and the external terminal on the battery can side are connected after the power storage element is accommodated in the battery can, the current collecting lead is lengthened to adjust the connection position. In addition, it is necessary to perform connection work in the battery can, so that workability is deteriorated.

  Therefore, when using a large-area stacked-type power storage element, it is preferable that the handling property at the time of manufacture is good so as not to be bent during transportation, and the connection work with external terminals is also easy. .

  In addition, it is a secondary battery that can be handled without deforming the storage element even if it has a large-area stacked storage element, and is assembled in the battery can so that the storage element does not bend. A method of manufacturing a secondary battery that can be connected to the current collecting lead and the external terminal easily is preferable.

  Therefore, in view of the above problems, the present invention can handle a storage battery without deforming the storage element even if it is a secondary battery including a large-area stacked storage element. Another object of the present invention is to provide a secondary battery that can be housed in a battery can and can easily connect the current collecting lead and the external terminal, and a method for manufacturing the secondary battery.

  In order to achieve the above object, the present invention provides a secondary battery including a battery can that contains an electricity storage element including an electrode group in which a plurality of layers of a positive electrode plate and a negative electrode plate are stacked via a separator and is filled with an electrolyte solution. The battery can includes a main container and an external terminal having a smaller volume than the main container and connected to a current collecting lead provided in the electrode group, the electrode group is laminated, and the current collecting lead is A sub-container connected to the external terminal and in which the power storage element is constructed, wherein the sub-container in which the power storage element is constructed and the main container are assembled.

  According to this configuration, since the power storage element is constructed by previously laminating the electrode group on the sub-container, it is configured to be directly stacked on the support, and can be handled without deforming the power storage element. A secondary battery that can be accommodated in a battery can without being bent even if it is a large-sized power storage element having a heavy dead weight can be obtained. In addition, since the current collecting lead is directly connected to the sub-container in which the electrode group is laminated, even if the current collecting lead has a short length, the connection work with the external terminal becomes easy. Further, since the current collecting lead is directly connected on the sub container, various welding methods can be adopted, and the degree of freedom in designing the external terminal connecting method is increased.

  According to the present invention, in the secondary battery configured as described above, the length of the current collecting lead is not more than twice the thickness of the electrode group. According to this configuration, since the current collecting lead is directly connected to the external terminal provided in the sub-container that supports the electrode group, the length of the current collecting lead can be shortened, for example, about twice or less the thickness of the electrode group. As a result, it is easy to clean the leads at the time of connection work, and the connection work is easier than connecting a relatively long current collecting lead in the box-shaped outer case.

  According to the present invention, in the secondary battery configured as described above, the sub-container has a flat surface on which the electrode groups are stacked. According to this configuration, since the electrode group is laminated on a flat surface, the stacking operation can be easily performed, and the electrode group can be handled while maintaining the plane of the stacked electrode group. Does not deform and does not peel off, and the occurrence of troubles such as static electricity and short circuits can be suppressed.

  According to the present invention, in the secondary battery configured as described above, the sub-container is box-shaped and includes an opening in a direction opposite to a surface on which the electrode groups are stacked. According to this structure, if it is box shape, the frame intensity | strength of a subcontainer will increase and it can carry without deform | transforming an electrode group.

  According to the present invention, in the secondary battery having the above-described configuration, the external terminal protrudes toward the opening. According to this configuration, the external terminal can be provided so as to be housed in the box shape.

  According to the present invention, in the secondary battery configured as described above, the sub-container has a box shape, and the electrode group is stacked on a surface having an opening. According to this structure, if it is box shape, the frame intensity | strength of a subcontainer will increase and it can carry without deform | transforming an electrode group.

  According to the present invention, in the secondary battery configured as described above, the external terminal is provided on a side surface portion that forms the opening. According to this configuration, since the external terminal is disposed on the side surface side of the electrode group, it is possible to easily connect the external device on the side.

  According to the present invention, in the secondary battery having the above-described configuration, a first insulating member is interposed on a surface of the sub-container on which the electrode groups are stacked. According to this configuration, electrical insulation between the electrode group and the container can be reliably achieved.

  According to the present invention, in the secondary battery configured as described above, the first insulating member has an area larger than an area of the electrode group. According to this configuration, in addition to the electrical insulation between the electrode group and the container, the surface strength of the electrode group can be improved.

  According to the present invention, in the secondary battery configured as described above, a fixing member for fixing the electrode group to the sub container is provided. According to this configuration, it is possible to reliably prevent the lateral displacement that shifts in the stacking surface direction and the vertical shift that shifts in the stacking direction in the electrode group that is stacked in the sub-container, and it is caused by shifting or peeling during carrying. Occurrence of failures such as static electricity and short circuits can be suppressed.

  According to the present invention, in the secondary battery configured as described above, a second insulating member that sandwiches the electrode group is provided in cooperation with the first insulating member, and a predetermined pressure is applied to the sandwiching body via the fixing member. In this state, it is pressed against the sub-container and fixed. According to this structure, since an electrode group is clamped using a 1st, 2nd insulating member, the insulation of an electrode group can be aimed at reliably. In addition, since it is fixed in a state where a predetermined pressure is applied, it is possible to maintain an appropriate degree of adhesion between a plurality of electrode plates constituting the electrode group, and the electrode group contacts other members during handling. Thus, it can be prevented from being deformed or damaged.

  According to the present invention, in the secondary battery having the above-described configuration, the second insulating member is provided with a recess that allows the fixing member to be recessed and mounted, and the fixing member does not protrude from the surface of the second insulating member. It is characterized by being attached to. According to this configuration, there is no protrusion on the surface of the second insulating member facing the main container, and the surface becomes flat, and no extra space is generated.

  In the secondary battery having the above structure according to the present invention, the main container is an exterior case that integrally accommodates the electrode group, and the sub-container is a lid member that seals the exterior case. Yes. According to this configuration, the electrode group is directly laminated on the lid member, and then assembled together with the outer case and sealed, so that the number of assembling steps can be reduced and the assembling cost can be reduced. In addition, since the electrodes are laminated in advance on the lid member, the electrode group can be carried without being deformed, and a secondary battery excellent in handling property at the time of manufacture can be obtained.

  Further, the present invention is a method for manufacturing a secondary battery including a battery can that contains a power storage element including an electrode group in which a plurality of layers of a positive electrode plate and a negative electrode plate are laminated via a separator and is filled with an electrolyte solution, The battery can is composed of a main container and a sub container having a smaller volume than the main container, an external terminal is provided on the sub container, the electrode group is stacked on the sub container, and a current collecting lead provided on the electrode group Is connected to the external terminal to construct an electrode group unit, and then the electrode group unit and the main container are assembled and sealed.

  According to this configuration, the electrode group is directly stacked on the sub-container constituting the battery can to produce the power storage element, so that the power storage element is directly constructed on the support and is stored in the main container as it is. It is possible to handle the storage element without deforming it, and it can be accommodated in the battery can without bending the storage element, and the connection work between the current collector lead and the external terminal is easy. A manufacturing method can be obtained.

  According to the present invention, in the method of manufacturing a secondary battery having the above-described configuration, a first step of laminating the electrode group on the sub container, a current collecting lead is provided on the electrode group, and the current collecting lead is provided on the sub container. A second step of fixing the electrode group by connecting to an external terminal; a third step of assembling a sub-container to which the electrode group is fixed and the main container to construct a battery can; and electrolysis in the battery can And a fourth step of injecting the liquid. According to this configuration, the electrode group having a configuration in which a plurality of layers of the positive electrode plate, the negative electrode plate, and the separator are stacked is housed in the battery can without bending, and the connection work between the current collecting lead and the external terminal is facilitated and safe. This is a reliable method for manufacturing a secondary battery. For this reason, the yield is not deteriorated due to a short circuit or the like, and an efficient manufacturing method in which no material loss occurs.

  According to the present invention, the battery can is composed of a main container and a sub container having a smaller volume than the main container, the sub container is provided with an external terminal, the electrode group is stacked on the sub container, and the electrode group Since the current collector lead to be provided is connected to the external terminal and then assembled together with the main container to construct the battery can, even a secondary battery having a large-area stacked storage element is stacked. A secondary battery that can be handled without deforming the storage element, can be accommodated in the battery can without bending the storage element, and can easily connect the current collecting lead to the external terminal, and The manufacturing method can be obtained.

It is a perspective view which shows the outline | summary of 1st embodiment of the secondary battery which concerns on this invention. It is a schematic sectional drawing of the secondary battery of said 1st embodiment. It is a schematic sectional drawing which shows 2nd embodiment of the secondary battery which concerns on this invention. It is a schematic sectional drawing which shows 3rd embodiment of the secondary battery which concerns on this invention. It is a schematic perspective view which shows the 1st modification with which the screw-shaped fixing member was mounted | worn. It is a principal part enlarged view of a 1st modification. It is a schematic perspective view which shows the 2nd modification with which the band-shaped fixing member was mounted | worn. It is a principal part enlarged view of the 2nd modification. It is a disassembled perspective view of a secondary battery. It is a disassembled perspective view of the electrode group with which a secondary battery is provided. It is a perspective view which shows the completed product of a secondary battery. It is a schematic sectional drawing of an electrode group.

  Embodiments of the present invention will be described below with reference to the drawings. Moreover, the same code | symbol is used about the same structural member, and detailed description is abbreviate | omitted suitably.

  A lithium secondary battery will be described as the secondary battery according to the present invention. For example, the secondary battery RB1 according to this embodiment shown in FIG. 1 is a stacked lithium secondary battery, and includes a stacked electrode group 1 in which a plurality of positive electrode plates and negative electrode plates are stacked via a separator. This is a configuration provided. Further, by increasing the area of each electrode plate and increasing the number of stacked layers, it becomes a secondary battery having a relatively large capacity, and can be applied to a storage battery for electric vehicles, a storage battery for power storage, and the like.

  In addition, a battery can containing a power storage element including an electrode group 1 in which a plurality of layers of a positive electrode plate and a negative electrode plate are laminated via a separator and filled with an electrolyte solution is smaller in volume than the main container CA1 and the main container. It is comprised with subcontainer CA2.

  Moreover, the external terminal 7 is provided in sub container CA2. And the electrode group 1 is laminated | stacked on this subcontainer CA2, the current collection lead 5 provided in this electrode group 1 is connected with the external terminal 7, and it is set as the structure which builds an electrical storage element in subcontainer CA2 previously. Therefore, the electrode group unit in which the power storage element is installed on the sub container CA2 serving as a support is configured in advance, and the power storage element can be handled without being deformed.

  Then, the main container CA1 is assembled to the constructed electrode group unit to constitute a battery can. Further, the main container CA1 and the sub container CA2 are welded, for example, to produce a sealed battery can, and an electrolyte is injected from a liquid injection port provided in either the main container CA1 or the sub container CA2. A secondary battery RB1 is produced.

  Next, specific configurations of the stacked lithium secondary battery RB including the outer case 11 and the lid member 12 and the electrode group 1 will be described with reference to FIGS.

  As shown in FIG. 6, the stacked lithium secondary battery RB has a rectangular shape in plan view, and includes an electrode group 1 in which a positive electrode plate, a negative electrode plate, and a separator, each of which is rectangular, are stacked. Moreover, it accommodates in the battery can 10 comprised from the exterior case 11 and the cover member 12 which are provided with the bottom part 11a and the side parts 11b-11e, and is made into a box shape, and the side surface (for example, side part 11b, 11c is configured to perform charging / discharging from an external terminal 11f (corresponding to the external terminal 7 described above) provided on two opposite side surfaces of 11c.

  The electrode group 1 has a configuration in which a plurality of layers of a positive electrode plate and a negative electrode plate are laminated via a separator. As shown in FIG. 7, the positive electrode current collector 2b (for example, an aluminum foil) is coated with a positive electrode active material on both surfaces. The positive electrode plate 2 having the positive electrode active material layer 2a formed thereon and the negative electrode plate 3 having the negative electrode active material layer 3a formed of the negative electrode active material formed on both surfaces of the negative electrode current collector 3b (for example, copper foil) It is laminated through.

  Although the separator 4 insulates the positive electrode plate 2 and the negative electrode plate 3 from each other, lithium ions can be transferred between the positive electrode plate 2 and the negative electrode plate 3 through the electrolyte filled in the outer case 11. It has become.

Here, as the positive electrode active material of the positive electrode plate 2, oxides of lithium is contained _(such as _{LiCoO 2, LiNiO 2, LiFeO 2} , LiMnO 2, LiMn 2 O 4) or a part of the transition metal in the oxide And a compound in which is substituted with other metal elements. Among these, in a normal use, if a material that can use 80% or more of lithium held in the positive electrode plate 2 for the battery reaction is used as the positive electrode active material, safety against accidents such as overcharge can be improved. Examples of such a positive electrode active material include a compound having a spinel structure such as LiMn ₂ O ₄ and LiMPO ₄ (M is at least one element selected from Co, Ni, Mn, and Fe). And a compound having an olivine structure represented by: Especially, the positive electrode active material containing at least one of Mn and Fe is preferable from a viewpoint of cost. Furthermore, it is preferable to use LiFePO ₄ from the viewpoint of safety and charging voltage.

  Further, as the negative electrode active material of the negative electrode plate 3, a material containing lithium or a material capable of inserting / removing lithium is used. In particular, in order to have a high energy density, it is preferable to use a lithium insertion / extraction potential close to the deposition / dissolution potential of metallic lithium. A typical example is natural graphite or artificial graphite in the form of particles (scale-like, lump-like, fibrous, whisker-like, spherical and pulverized particles).

  In addition to the positive electrode active material of the positive electrode plate 2, and in addition to the negative electrode active material of the negative electrode plate 3, a conductive material, a thickener, a binder, and the like may be contained. The conductive material is not particularly limited as long as it is an electron conductive material that does not adversely affect the battery performance of the positive electrode plate 2 or the negative electrode plate 3. For example, carbon black, acetylene black, ketjen black, graphite (natural graphite, artificial graphite) ), Carbonaceous materials such as carbon fibers, conductive metal oxides, and the like can be used.

  As the thickener, for example, polyethylene glycols, celluloses, polyacrylamides, poly N-vinyl amides, poly N-vinyl pyrrolidones and the like can be used. The binder serves to hold the active material particles and the conductive material particles together, and includes a fluorine-based polymer such as polyvinylidene fluoride, polyvinyl pyridine and polytetrafluoroethylene, a polyolefin polymer such as polyethylene and polypropylene, Styrene butadiene rubber or the like can be used.

  Moreover, as the separator 4, it is preferable to use a microporous polymer film. Specifically, films made of a polyolefin polymer such as nylon, cellulose acetate, nitrocellulose, polysulfone, polyacrylonitrile, polyvinylidene fluoride, polypropylene, polyethylene, polybutene can be used.

  Moreover, it is preferable to use an organic electrolytic solution as the electrolytic solution. Specifically, as an organic solvent of the organic electrolyte, esters such as ethylene carbonate, propylene carbonate, butylene carbonate, diethyl carbonate, dimethyl carbonate, methyl ethyl carbonate, and γ-butyrolactone, tetrahydrofuran, 2-methyltetrahydrofuran, dioxane, dioxolane , Diethyl ether, dimethoxyethane, diethoxyethane, methoxyethoxyethane, and other ethers, dimethyl sulfoxide, sulfolane, methyl sulfolane, acetonitrile, methyl formate, and methyl acetate can be used. These organic solvents may be used alone or in combination of two or more.

Further, the organic solvent may contain an electrolyte salt. Examples of the electrolyte salt include lithium perchlorate (LiClO ₄ ), lithium borofluoride, lithium hexafluorophosphate, trifluoromethanesulfonic acid (LiCF ₃ SO ₃ ), lithium fluoride, lithium chloride, lithium bromide, and iodide. And lithium salts such as lithium and lithium tetrachloroaluminate. In addition, these electrolyte salts may be used independently and may be used in mixture of 2 or more types.

  The concentration of the electrolyte salt is not particularly limited, but is preferably about 0.5 to about 2.5 mol / L, and more preferably about 1.0 to 2.2 mol / L. When the concentration of the electrolyte salt is less than about 0.5 mol / L, the carrier concentration in the electrolytic solution is lowered, and the resistance of the electrolytic solution may be increased. On the other hand, when the concentration of the electrolyte salt is higher than about 2.5 mol / L, the dissociation degree of the salt itself is lowered, and there is a possibility that the carrier concentration in the electrolytic solution does not increase.

  The battery can 10 includes an outer case 11 and a lid member 12, and is made of iron, nickel-plated iron, stainless steel, aluminum, or the like. Further, in the present embodiment, as shown in FIG. 8, the battery can 10 is formed so that the outer shape is substantially a flat rectangular shape when the outer case 11 and the lid member 12 are combined. ing.

  The outer case 11 is a box shape having a bottom portion 11a having a substantially rectangular bottom surface and four side portions 11b to 11e erected from the bottom portion 11a, and the electrode group 1 is accommodated inside the box shape. To do. The electrode group 1 includes a positive current collecting lead coupled to a current collecting tab of the positive electrode plate and a negative current collecting lead coupled to the current collecting tab of the negative electrode plate, and is electrically connected to these current collecting tabs. External terminals 11 f are provided on the sides of the outer case 11. The external terminal 11f is provided, for example, at two locations on the opposite two side portions 11b and 11c. Reference numeral 10a denotes a liquid injection port from which an electrolytic solution is injected.

  After the electrode group 1 is accommodated in the outer case 11 and each current collecting lead is connected to an external terminal, the lid member 12 is fixed to the opening edge of the outer case 11. Then, the electrode group 1 is sandwiched between the bottom portion 11 a of the outer case 11 and the lid member 12, and the electrode group 1 is held inside the battery can 10. The lid member 12 is fixed to the exterior case 11 by, for example, laser welding. Further, the connection between the current collecting lead and the external terminal can be performed by using a conductive adhesive or the like in the case where the current collector lead is not attacked by the electrolytic solution other than welding such as ultrasonic welding, laser welding, and resistance welding.

  As described above, the lithium secondary battery RB includes the electrode group 1 in which a plurality of layers of the positive electrode plate 2 and the negative electrode plate 3 are stacked with the separator 4 interposed therebetween, and the exterior case that contains the electrode group 1 and is filled with the electrolyte solution. 11, an external terminal 11 f provided on the outer case 11, positive and negative current collecting leads that electrically connect the positive and negative electrode plates and the external terminal 11 f, and a lid member 12 attached to the outer case 11. It is a configuration.

  As shown in FIG. 9, the electrode group 1 accommodated in the outer case 11 includes a positive electrode plate 2 having a positive electrode active material layer 2a formed on both surfaces of the positive electrode current collector 2b and a negative electrode on both surfaces of the negative electrode current collector 3b. Since the negative electrode plate 3 on which the active material layer 3a is formed is laminated via the separator 4, and the separator 4 is disposed on both end faces, the upper surface of the laminated electrode group 1 is provided with an insulating separator 4. Are stacked. Therefore, the lid member 12 can be brought into direct contact with this surface, and can be pressed with a predetermined pressure via the lid member.

  Moreover, in the secondary battery of the structure which produces the electrode group 1 outside a battery can and accommodates the produced electrode group in a battery can, each is a foil-like positive electrode plate, a negative electrode plate, and a separator dozens of layers It is important to accommodate the stacked electrode group 1 in a battery can without being deformed or bent.

  If the electrode group 1 is deformed or bent, static electricity is generated when the electrodes constituting the electrode plate are rubbed or a gap is formed between the electrodes, and the risk of short-circuiting due to contamination of foreign matters increases. Therefore, in this embodiment, by constructing the electrode group 1 directly on one of the containers constituting the battery can, the electrode group 1 that is a laminated body is not bent as a structure that is laminated directly on the support. It can be handled. Next, a configuration example of the secondary battery in which the electrode group 1 is constructed on one of the containers constituting the battery can will be described with reference to FIGS.

  In the secondary battery RB1 of the first embodiment shown in FIG. 1, as described above, the battery can is composed of the main container CA1 and the sub container CA2 having a smaller volume than the main container, and the sub container CA2 has an external terminal. 7 (corresponding to the external terminal 11f described above), the electrode group 1 is laminated on the sub-container CA2, the current collecting lead 5 provided on the electrode group 1 is connected to the external terminal 7, and then assembled together with the main container CA1. Battery cans.

  Sub container CA2 may be flat or box-shaped. For example, as shown in the side view of FIG. 2, if the sub container CA <b> 2 has a flat plate shape, the power storage element including the electrode group 1 can be integrally assembled on the flat sub container CA <b> 2 in advance.

  Further, if the surface on which the electrode group 1 is laminated is flat, the electrode group 1 is laminated on a flat surface, so that the laminating operation can be easily performed, and the flatness of the laminated electrode group 1 is maintained. It can be handled as it is, and the electrode plate, separator, etc. are not deformed and do not peel off, and the occurrence of troubles such as static electricity and short circuit can be suppressed.

  For example, when the electrode group 1 is laminated outside the battery can and this laminated electrode group 1 is transported using a two-claw type support member, the portion not supported by the claw portion is bent. The electrodes are rubbed and gaps are formed between the electrodes. Moreover, even if it conveys using a flat support member, when accommodating in a battery can, it is difficult to accommodate a laminated body, without bending.

  Therefore, according to the present embodiment in which a laminated body is directly constructed in the sub-container CA2 constituting the battery can, even a large power storage element having a heavy weight can be accommodated in the battery can without being bent. A secondary battery can be obtained. Further, since the connection work between the current collecting lead 5 and the external terminal 7 is performed on the sub container CA2 on which the electrode group 1 is laminated, the connection work is facilitated. In addition, since the connection work can be performed using a wide space on the sub-container CA2, various welding methods can be adopted, which is preferable because the degree of freedom in designing the external terminal connection method is increased.

  When the external terminal 7 is provided in the flat sub container CA2, the external terminal 7 is provided so as to penetrate the flat sub container CA2, and the current collector is collected at the end of the external terminal exposed on the mounting surface side of the electrode group 1. Since the lead 5 is connected, the current collecting lead 5 connected to the current collecting tab of each electrode plate can be connected and fixed in a slightly curved shape. Therefore, the length of the current collecting lead 5 can be shortened.

  Thus, since the current collecting lead 5 is directly connected to the external terminal 7 provided in the sub container CA2 that supports the electrode group 1, the length of the current collecting lead 5 can be shortened, for example, twice the thickness of the electrode group 1 Shortening to the following extent is preferable because it facilitates the handling of the leads during the connection work and facilitates the connection work compared to connecting a relatively long current collecting lead in the box-shaped outer case.

  In order to electrically insulate the electrode group 1 from the container, the electrode group 1 is preferably sandwiched between insulating members having a predetermined thickness. For example, the first insulating member 6A is interposed on the surface to be laminated. With such a configuration, electrical insulation between the electrode group 1 and the container can be reliably achieved. Moreover, it is good also as a structure which provides the 2nd insulating member 6B which clamps the electrode group 1 in cooperation with 6A of 1st insulating members.

  If the configuration includes the first insulating member 6A and the second insulating member 6B, the electrode group 1 is sandwiched between the first and second insulating members 6A and 6B, so that the insulating property of the electrode group 1 is reliably achieved. In addition, it is possible to better prevent the electrode group 1 from being deformed or damaged due to contact with other members during handling.

  For example, PTFE having a thickness of 3 mm can be used as the first and second insulating members 6A and 6B.

  The first insulating member 6 </ b> A and the second insulating member 6 </ b> B preferably have an area larger than the area of the electrode group 1. If it is this structure, in addition to aiming at the electrical insulation of the electrode group 1 and a container, the surface strength of the electrode group 1 can be improved.

  Moreover, it is preferable that the electrode group 1 laminated | stacked on sub container CA2 is being fixed to sub container CA2 via the fixing member. Further, it is preferable that the first and second insulating members 6A and 6B have a larger area than the area of the electrode group 1, and the fixing member is mounted via the first and second insulating members 6A and 6B.

  With the configuration in which the electrode group 1 is fixed, the electrode group 1 stacked in the sub-container CA2 can be reliably prevented from being shifted laterally and vertically shifted in the stacking direction. It is preferable because the occurrence of troubles such as static electricity and short circuit caused by peeling or peeling can be suppressed.

  Next, a configuration example in which the fixing member is mounted via the first and second insulating members 6A and 6B will be described with reference to FIGS.

  For example, as in the first modification shown in FIG. 4A, the electrode group 1 is connected to the first and second insulating members 6A and 6B using a screw member 8A that penetrates the first and second insulating members 6A and 6B. At the same time, it can be fixed to the sub container CA2. Moreover, when mounting this screw-shaped fixing member, it is preferable to hold the electrode group 1 firmly with a predetermined pressure applied using the first and second insulating members 6A and 6B. Thus, if it is the structure fixed in the state which applied the predetermined pressure, while being able to aim at the insulation of the electrode group 1 reliably, the adhesiveness of the some electrode plates which comprise the electrode group 1 is moderate. It is possible to maintain a high degree of adhesion. Moreover, it can prevent that the electrode group 1 contacts with another member, and is deform | transformed or damaged.

  Further, as in the second modification shown in FIG. 5A, the electrode group 1 is fixed to the sub container CA2 together with the first and second insulating members 6A and 6B by using the band member 8B instead of the screw member 8A. be able to. Even in the configuration in which the band-shaped fixing member is mounted, it is preferable to firmly hold the electrode group 1 in a state where a predetermined pressure is applied using the first and second insulating members 6A and 6B. Thus, by fixing in a state where a predetermined pressure is applied using the band member 8B, the insulating property of the electrode group 1 can be reliably achieved, and a plurality of electrode plates constituting the electrode group 1 can be connected to each other. The degree of adhesion can be maintained at an appropriate degree of adhesion. Moreover, it can prevent that the electrode group 1 contacts with another member, and is deform | transformed or damaged.

  The surface of the second insulating member 6B to which the fixing member such as the screw member 8A or the band member 8B is attached is preferably formed with a recess so that these fixing members do not protrude. For example, when the screw member 8A is used, as shown in FIG. 4B, a hole-shaped recess 6Ba that can sink the head of the screw member 8A is provided. When the band member 8B is used, as shown in FIG. 5B, a groove-like recess 6Bb into which the band member 8B can be recessed is provided. If it is such a structure, a protrusion will not exist on the surface of the 2nd insulating member 6B which opposes main container CA1, it will become flat, and an extra space will not arise. Further, both the screw member 8A and the band member 8B are preferably members having heat resistance, chemical resistance and insulation, and for example, made of resin such as PTFE, PEEK, ETFE, FEP, PFA, etc. are used. be able to.

  Next, a configuration example in which the sub container CA2 has a box shape will be described with reference to FIGS. 3A and 3B.

  FIG. 3A shows a secondary battery RB2 of a second embodiment having a configuration in which the opening is directed downward and the electrode group 1 is stacked on the opposite side of the opening. Thus, if it is box-shaped subcontainer CA2A of the structure provided with the opening part in the reverse direction of surface CAa which laminates electrode group 1, the frame intensity as a container will increase and electrode group 1 will not be changed. Can be handled.

  Moreover, even if the secondary battery RB2 with the opening portion facing downward is provided with the external terminal 7 protruding on the surface CAb on the opening portion side, the protruding portion can be accommodated in the box-shaped frame. Therefore, when the secondary battery RB2 is handled, the external terminal 7 can be protected, and contact with other members or devices can be prevented from being damaged.

  The secondary battery RB3 of the third embodiment shown in FIG. 3B is an example provided with a box-shaped sub-container CA2B having a configuration in which the electrode group 1 is stacked on the surface CAb on the opening side with the opening portion facing upward. . Even in the configuration provided with such a sub container CA2B, the frame strength as a container is increased, and the electrode group 1 can be handled without being deformed.

  Further, in the sub container CA2B with the opening portion facing upward, the external terminal 7 may be provided on the side surface portion CAc that forms the opening portion. With this configuration, since the external terminal 7 is disposed on the side surface side of the electrode group 1, it is possible to easily connect to an external device on the side.

  The main container CA1 and the sub containers CA2, CA2A, CA2B constituting the battery can described above correspond to, for example, the outer case 11 in which the main container CA1 integrally accommodates the electrode group 1, and the sub containers CA2, CA2A, CA2B. Corresponds to the lid member 12 that seals the exterior case 11.

  Since the lid member 12 has a smaller volume than the outer case 11, it can be said that the electrode group 1 is laminated on a constituent member having the second largest volume constituting the battery can. Further, since the lid member 12 has an area larger than the area of the electrode group 1, it can be said that the electrode group 1 is directly laminated on a constituent member having an area larger than that of the electrode group 1.

  If the electrode group 1 is laminated on the lid member 12, the electrode group 1 is laminated directly on the lid member 12, and then assembled and sealed together with the outer case 12, which reduces the number of assembly steps and reduces the assembly cost. Can be reduced. Moreover, since it is previously laminated on the lid member 12, the electrode group 1 can be carried without being deformed, and it is preferable as a secondary battery having excellent handling properties at the time of manufacture.

  Next, even a secondary battery including a large-area stacked storage element can be handled without being deformed as a configuration in which the stacked storage element is directly stacked on a support. A method for manufacturing a secondary battery, in which the element can be accommodated in the battery can without bending and the connecting work between the current collecting lead and the external terminal is facilitated, will be further described.

  In the method for manufacturing a secondary battery according to the present embodiment, a battery can is composed of a main container and a sub container having a smaller volume than the main container, an external terminal is provided in the sub container, and an electrode group is provided in the sub container. In this manufacturing method, the current collecting leads provided in the electrode group are connected to an external terminal to construct an electrode group unit, and then the electrode group unit and the main container are assembled and sealed.

  If this manufacturing method is used, the electrode group is directly stacked on the sub-container that constitutes the battery can, and is housed in the main container as it is. Therefore, the stacked power storage elements can be handled without being deformed. The element can be accommodated in the battery can without being bent, and a connecting method between the current collecting lead and the external terminal is facilitated.

  In addition, the manufacturing method includes a first step of laminating the electrode group on the sub-container, a current collecting lead provided in the electrode group, and the electrode group is fixed by connecting the current collecting lead to an external terminal provided in the sub-container. It can be said that it has two steps, a third step of assembling a battery can by assembling a sub-container with a fixed electrode group and a main vessel, and a fourth step of injecting an electrolyte into the battery can. .

  With this configuration, the electrode group having a configuration in which a plurality of layers of the positive electrode plate, the negative electrode plate, and the separator are stacked is accommodated in the battery can without bending, and the connection work between the current collecting lead and the external terminal is facilitated and safety is ensured. This is a reliable method for manufacturing a secondary battery. Therefore, it is preferable to be an efficient manufacturing method in which the yield does not deteriorate due to a short circuit or the like and no material loss occurs.

  Since the secondary battery manufactured by the above-described method of the present invention produces an electrode group as a laminate on a flat sub-container, the stacking operation of the electrode group becomes easy. Further, the electrical connection work for connecting the current collecting lead and the external terminal is facilitated, and the workability at the time of manufacture is improved. Furthermore, since it is configured to be directly laminated on the support, even a large-area laminate can be handled without bending the electrode group that is the laminate, and on the electrode plate constituting the laminate The risk of short-circuiting due to foreign matters can be reduced without rubbing the electrodes or creating a gap between the electrodes.

  As described above, according to the secondary battery of the present invention, the battery can is provided with the main container and the external terminal having a smaller volume than the main container and connected to the current collecting lead provided in the electrode group, Since the group is stacked and the current collecting lead is connected to the external terminal, and the sub-container in which the power storage element is constructed, the power storage element is constructed in advance in the sub-container constituting the battery can . For this reason, even a secondary battery having a large-area stacked storage element can be handled without deforming the stacked storage element, and the storage element can be accommodated in the battery can without bending. It is possible to obtain a secondary battery that can be accommodated and that facilitates connection work between the current collecting lead and the external terminal.

  Further, according to the method for manufacturing a secondary battery according to the present invention, the battery can is composed of a main container and a sub-container having a smaller volume than the main container, the sub-container is provided with an external terminal, and the sub-container Since the electrode group unit is constructed by stacking the electrode group and connecting the current collecting leads provided in the electrode group to the external terminal, and then assembling and sealing the electrode group unit and the main container, the support body This is a manufacturing method in which the electrode group unit on which the power storage element is constructed is housed in the main container as it is. For this reason, even a secondary battery having a large-area stacked storage element can be handled without deforming the stacked storage element, and the storage element can be accommodated in the battery can without bending. It is possible to obtain a method for manufacturing a secondary battery that can be accommodated and that facilitates connection work between the current collecting lead and the external terminal.

  Further, since the current collecting lead is directly connected on the sub container, the lead length can be shortened. Furthermore, various welding methods can be adopted, and the degree of freedom in designing the external terminal connection method is increased.

  In addition, the stacked electrodes and separators are not deformed and do not peel off, and it is possible to suppress the occurrence of troubles such as static electricity and short circuits, so that the yield does not deteriorate due to short circuits and no material loss occurs. It becomes an efficient manufacturing method.

  Therefore, the secondary battery and the manufacturing method thereof according to the present invention can be suitably used for a large-capacity storage battery that is required to be increased in size and stabilized in performance and the manufacturing method thereof.

DESCRIPTION OF SYMBOLS 1 Electrode group 2 Positive electrode plate 3 Negative electrode plate 4 Separator 5 Current collection lead 6A First insulating member 6B Second insulating member 7 External terminal 8A Screw member (fixing member)
8B Band member (fixing member)
10 Battery Can 11 Exterior Case 12 Lid Member CA1 Main Container CA2 Sub Container RB, RB1 to RB3 Secondary Battery

Claims (15)

A secondary battery comprising a battery can containing an electricity storage element including an electrode group in which a plurality of layers of a positive electrode plate and a negative electrode plate are laminated via a separator and filled with an electrolyte solution,
The battery can includes a main container,
The volume is smaller than that of the main container, and includes an external terminal connected to a current collecting lead included in the electrode group, the electrode group is stacked, the current collecting lead is connected to the external terminal, and the power storage element is constructed. A sub-container, and
A secondary battery, wherein the sub-container in which the power storage element is constructed and the main container are assembled. The secondary battery according to claim 1, wherein a length of the current collecting lead is not more than twice a thickness of the electrode group. The secondary battery according to claim 1, wherein the sub-container has a flat surface on which the electrode group is laminated. The secondary battery according to claim 1, wherein the sub-container is box-shaped and has an opening in a direction opposite to a surface on which the electrode groups are stacked. The secondary battery according to claim 4, wherein the external terminal protrudes toward the opening. The secondary battery according to claim 1, wherein the sub-container has a box shape, and the electrode group is stacked on a surface having an opening. The secondary battery according to claim 6, wherein the external terminal is provided on a side surface that forms the opening. The secondary battery according to claim 1, wherein a first insulating member is interposed on a surface of the sub container on which the electrode group is laminated. The secondary battery according to claim 8, wherein the first insulating member has an area larger than an area of the electrode group. The secondary battery according to claim 9, further comprising a fixing member that fixes the electrode group to the sub container. A second insulating member that sandwiches the electrode group is provided in cooperation with the first insulating member, and the sandwiching body is pressed and fixed to the sub-container with a predetermined pressure applied through the fixing member. The secondary battery according to claim 10. The concave portion that allows the second insulating member to be mounted by being depressed, and the fixing member is mounted without protruding from the surface of the second insulating member. The secondary battery as described. The said main container is an exterior case which accommodates the said electrode group integrally, Comprising: The said sub container is a cover member which seals the said exterior case, The one in any one of Claim 1 to 12 characterized by the above-mentioned. Secondary battery. A method for producing a secondary battery comprising a battery can that contains a storage element including an electrode group in which a plurality of layers of a positive electrode plate and a negative electrode plate are laminated via a separator, and is filled with an electrolyte solution,
The battery can is composed of a main container and a sub container having a smaller volume than the main container, an external terminal is provided on the sub container, the electrode group is stacked on the sub container, and a current collecting lead provided on the electrode group Is connected to the external terminal to construct an electrode group unit, and then the electrode group unit and the main container are assembled and sealed. A first step of laminating the electrode group on the sub-container, and a second step of providing a current collecting lead on the electrode group, and fixing the electrode group by connecting the current collecting lead to an external terminal provided on the sub-container And a third step of assembling a battery can by assembling the sub-container to which the electrode group is fixed and the main vessel, and a fourth step of injecting an electrolyte into the battery can. The method for manufacturing a secondary battery according to claim 14.

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